Scouring pads



Jan 17, 1967 P. A. PLAssE ETAL 3,298,053

' SCOURNG PADS Filed Nov. 5, 1964 FIGZ.

INV TORS PAUL A. PLAS WILLIAM'C-JOHNSON AT TORN EY United States Patent O 3,298,053 SCOURING PADS Paul A. Plasse, Lexington, and William C. Johnson, Winchester, Mass., assignors to Arthur D. Little, Inc., Cambridge, Mass., a corporation of Massachusetts Filed Nov. S, 1964, Ser. No. 409,198 Claims. (Cl. 15--506) This invention relates to metal wool scouring pads.

More particularly, it lrelates to soap-filled scouring pads presenting a scouring surface of soap-filled steel wool and having the `back side of the pad provided with a protective backing sheet, the whole pad `being provided with a handle to factilitate grasping the pad for use in scourmg.

Soap-filled steel wool pads are, of course, a familiar household cleansing aid. Most commonly, these consist of a fairly thick pad of steel fibers, usually in the form of a flattened coil or cylinder, devoid of either a protective backing or a handle. Such pads have lcertain limitations and disadvantages. Since they have no handle or backing, the user ordina-rily grasps them with the bare fingers, and small slivers of steel often prick the users fingers. The soap filling washes out rather rapidly, and :the rustinhibitors (normally compounded into the soap) also usually rinse out with the soap; as a consequence, the steel wool -pad usually rusts very rapidly after the rst using, and thereafter tends to tear apart very easily and to leave rust stains.

Recently several backed pads have been devised and introduced, but these have ybeen somewhat unsatisfactory by reason of Ibeing thin and hard to hold and to lack the desirable |bulkiness of the common unbacked pads.

This invention overcomes these difficulties and drawbacks, providing an inexpensive light-weight pad of satisfactory bulk which can be conveniently grasped in the users fingers without risk of pricking the said fingers and in which the soap is ordinarily retained in the steel wool pad even through several occasions of use.

The invention will be readily understood `by reference to the accompanying drawings, in which FIGURE 1 is a top plan view of a scouring pad of this invention. FIG- URE 2 is an underside plan view of the same scouring pad. FIGURE 3 is a section on line 3 3 of FIGURE 1, and FIGURE 4 is similar to FIGURE 3 except that it shows the pad flexed as it might be when the users fingers are thrust through the loop formed by the pad proper and its attached handle. FIGURE 5 is a schematic representation of an arrangement of appratus suitable for manufacture of the subject scouring pads on a continuous basis.

The scouring Ipads of this invention are rectangular and may be of any convenient size, such as about 2 x 2%" or, expressed in metric units, about 5 X 7 cm., the precise dimensions 'being a matter of choice. The pads consist, essentially, of three separate layers, namely, a layer of soap-impregnated, corrugated steel wool, shown as 1 in FIGURES 2, 3, and 4, a rectangularly embossed flexible backing layer of a thermoplastic sheeting, shown as 2 in FIGURES 3 and 4, and, in the pad illustrated in FIGURES 1, 3, and 4, `a flexible loop-forming handle of a unitary plastic netting shown as 4 in FIGURES l, 3, and 4.

As an alternative to the loop style handle illustrated, the netting may |be bonded to the backing sheet along a single relatively narrow zone passing substantially through the Imid-point of the backing sheet, which zone may extend either laterally, longitudinally, or diagonally. Another permissible lbut not preferred variation is to seal the netting to the longitudinal edges of the pad.

3,298,053 Patented Jan. 17, 1967 It is to be noted that, for the sake of indicating more clearly in FIGURE 2 the corrugations 6 in steel wool mat 1, the full mat of fibers is shown only in two diagonally opposite corner areas of the drawing; nevertheless, in `reality the steel wool fibers will be distributed in uniform lthickness along and across the whole length and 'breadth of the pad, as will be obvious from the discription of their construction.

Embossed ybacking layer 2 is bonded to steel Wool 1 by heat sealing, and is in turn thermally vbonded to handle 4 along end-zones 5, in the pad illustrated. The embossing of the backing not only results in greater bulkiness and improved scouring action, ybut also provides a plurality of shielded reservoirs for soap adjacent to the steel Wool web, which prevents rapid exhaustion of the soap during use of the pad. The backing layer 2 and steel wool layer 1 are bonded more firmly to each other along their peripheral edges than interiorly; as a consequence, the Acorrugations 6 of steel wool layer 1 will in general terminate just shont of the pad edges, as shown in FIG- URE 2. Along the peripheral edges of the pad, the steel wool is substantially completely embedded in the plastic backing sheet, thus imparting increased strength and resistance to wear. Over the balance of the pad area, the backing is bonded only to the surface fibers of the steel wool web; in this way the bulkiness imparted to the steel wool `by the corrugation is retained, greatly improving the scouring action.

The scouring pads of this invention such as illustrated in FIGURES 1-4 may be manufactured yby equipment shown schematically in FIGURE 5. In this drawing is shown an unwinding `coil 50 of matted steel wool fibers from which a mat of fibers 51 passes between a pair of closely spaced corrugating rolls 52, which impress the matted steel wool with corrugations runing perpendicular to the direction of trave-l and the steel wool fibers. Simultaneously, backing-layer material 53 is fed as a strip of flat film from a spool 54 over a roller 55 into close proximity to steel wool web 51 and travels with said web through a radiant heating zone 56, in `which the thermoplastic hacking material is heated to render it tacky and moldable. From this radiant heating zone the corrugated steel wool mat and the heat softened thermoplastic backing material pass together through a stack of chilled embossing rolls 57 which press them together, sealing the two layers together firmly on their outside edges and embossing the backing layer with oblong dimples whose concavities face the steel wool layer.

After leaving the embossing rolls, the partially assembled material is passed, with a strip of plastic netting 58 (unwinding from a supply coil .59) between a pair of heated rolls 60, one of which rolls is provided with longitudinal ridges which heat-seal the plastic netting strip at spaced intervals to the embossed `backing sheet and substantially completely em'bed the steel wool in the backing sheet in these zones of heat-sealing.

From heat-sealing rolls 60 the material passes under a soap fountain 61, between a pair of soap spreading rolls 62, and through :a cooling zone 63 to an indexed cutter 64 which cuts the now finished strip of pads into individual units, cutting through the spaced apart zones over which the netting strip 58 was heat-sealed to the backing sheet 2 in zones 5 by heat-sealing rolls 60.

It will be understood that the drawing of FIGURE 5 is entirely schematic and no attempt has been made to represent the several features shown on the same scale; bearings, supports, control means, power sources, etc., have been omitted. While showing a feasible arrangement of equipment for bringing the component parts of our soap pads together, forming them into a continuous band, and then severing this band 4into individual pads,

it is intended to represent only approximately the actual configurations impressed on the material in course of this processing.

As above indicated, w-hile the preferred soap pads of this invention have loop handles of thermoplastic netting sealed to the ends of the pads, we also contemplate pads in which the netting handles are sealed to the backing sheets only along single relatively narrow Zones passing substantially through the mid-point of the backing sheet. These may be manufactured in substantially the same manner as above described, wit-h relatively minor changes in the equipment. Thus, if it is desired to manufacture pads in which the netting handle is axed to the backing sheet only along a narrow zone extending laterally through its mid-point, embossing7 rolls 57 may be de signed to embed the steel wool additionally into the backing sheet in spaced laterally extending zones (corresponding to the pad ends); heat-sealing rolls 60 would then be operated to heat-seal 4the netting in laterally extending Zones intermediate of the so-dened pad ends, and the final cutting into individuall pads would be controlled to sever the continuous strip at these so-dened pad ends.

If it is desired to manufacture scouring pads in which the handles are attached along a single relatively narrow zone extending longitudinally through the pads center, heat-sealing rolls 60 may be replaced by a pair of opposed heated discs centered with respect to the traveling web. For diagonal attachment of the handles, heat-sealing roll 60 may be provided with suitable helical ridges instead of the longtudinal ridge described above.

The individual equipment units referred to in the foregoing description are standard in the industry and no invention is claimed as to them. Their adaptation and adjustment to suit them for manufacturing the soap pads of this invention is believed to be well within the skill of the art.

We have found that excellent soap pads can be made which contain about 2.5 grams of steel wool and about 0.5 gram of soap, though these amounts `are by no means critical. The backing layers may be made of almost any moderately flexible thermoplastic heat-sealable material, such as polyethylene, polypropylene, polystyrene, or vinyl plastic; we prefer low-density polyethylene in thickness of 0.003 to 0.010 inch, preferably about 0.006 inch. The plastic netting employed for the handle loops may also be of any flexible thermoplastic heat-scalable material, and We have found low-density polyethylene to be very satisfactory. Square-mesh or diagonal-mesh netting of 0015-0030 inch diameter strands and having from three to eight strands per inch has been found to be very satisfactory. T-he pads of this invention, having handles of plastic netting, are more convenient to use than pads with foamed plastic backing, paper backing, plastic lm loops or plastic tabs because they are easier to grip securely for use; the advantages of the pads of `this invention over such prior art pads are especially evident when wet and soapy.

While we have referred to the handle material as netting, it is to be understood that iby this term We do not mean merely a woven material in which Iche strands only lie in contact with each other where they cross, but rather a unitary material in which the strands have been heatsealed together where they cross each other, so that a section of this netting is really a single unitary piece of plastic having a net-like structure or configuration.

The soap with which the scouring lpads of this invention are impregnated may be selected from the large number of soap compositions available from the soap ndUSry- Preferably, the soap should contain a minor amount of a corrosion inhibitor to delay corrosion of the steel wool. A suitable formula is made from the following:

Parts Cocoanut oily fatty acids 46 Sodium hydroxide 5 Potassium hydroxide 4.25 Coloring agent 0.05 Corrosion inhibitor 1.0-5.0 Water 40 Examples of suitable corrosion inhibitors are sodium nitrite and sodium silicate, which may be used either singly or together.

The scouring pads of this invention may be used without fear that slivers of steel wool will injure the hands of the user, since the plastic backing layer protects the hands from contact with the steel wool. Corrugation of the steel wool mat and embossing of the backing sheet results in a dcsirably bulky pad which is convenient to use. Because the total amount of material used in each pad is relatively small, they can be made and sold at a relatively low cost, making Wide distribution .and use practical; because of their low cost, the purchaser can afford to discard a pad after a single days use, even though the pads Aare ordinarily usable for several different times.

The invention claimed is:

1. A scouring pad comprising (1) a layer of corrugated steel wool in which the corrugations are approximately perpendicular to the steel wool bers, (2) a backing sheet of thermoplastic lm deeply embossed over its non-peripheral area and thermally bonded to the surface fibers of one side of said layer of steel wool with the steel wool being substantially completely enbedded in said `backing sheet at the periphery of said pad vand at most only superfcially bonded to said backing sheet in the non-peripheral areas thereof, and (3) a handle of unitary thermoplastic netting thermally bonded to said embossed backing sheet along at least one relatively narrow zone within which the steel wool fibers are substantially completely embedded in said backing sheet.

2. A scouring pad according to claim 1 in which the steel Wool layer contains soap.

3. A scouring pad according to claim 1 in which the backing sheet is embossed with oblong dimples and in which the concavities of said dimples face the steel wool layer.

4. A scouring pad according to claim 1 in which the handle of unitary netting is bonded to opposite ends of the pad so as to form a closed loop therewith.

5. A scouring pad according to claim l1 in which the backing sheet and unitary netting grip are made of lowdensity polyethylene.

References Cited by the Examiner UNITED STATES PATENTS 2,735,721 2/1956 Rafferty 300-21 3,074,099 1/1963 Cameron 15--506 3,104,915 8/1963 Perkovich et al. 300-21 3,169,264 2/1965 Walker 15--209 X 3,182,346 5/1965 Winston 15-209 3,185,604 5/1965 Cameron 156-210 FOREIGN PATENTS 946,634 1/ 1964 Great Britain.

CHARLES A. WILLMUTH, Primary Examiner.

S. E. BECK, Assistant Examiner, 

1. A SCOURING PAD COMPRISING (1) A LAYER OF CORRUGATED STEEL WOOL IN WHICH THE CORRUGATIONS ARE APPROXIMATELY PERPENDICULAR TO THE STEEL WOOL FIBERS, (2) A BACKING SHEET OF THERMOPLASTIC FILM DEEPLY EMBOSSED OVER ITS NON-PERIPHERAL AREA AND THERMALLY BONDED TO THE SURFACE FIBERS OF ONE SIDE OF SAID LAYER OF STEEL WOOL WITH THE STEEL WOOL BEING SUBSTANTIALLY COMPLETELY EMBEDDED IN SAID BACKING SHEET AT THE PERIPHERY OF SAID PAD AND AT MOST ONLY SUPERFICIALLY BONDED TO SAID BACKING SHEET IN THE NON-PERIPHERAL AREAS THEREOF, AND (3) A HANDLE OF UNITARY THERMOPLASTIC NETTING THERMALLY BONDED TO SAID EMOBSSED BACKING SHEET ALONG AT LEAST ONE RELATIVELY NARROW ZONE WITHIN WHICH THE STEEL WOOL FIBERS ARE SUBSTANTIALLY COMPLETELY EMBEDDED IN SAID BACKING SHEET. 